The present invention relates to a front cap for a stem and to a bicycle stem equipped with such a front cap for fastening a handlebar to a bicycle. In the prior art, caps for stems have become known having a half-cylindrical recess for the cap to form-fit and to be securely attached to a bicycle handlebar.
In competitive cycling, wind resistance is a crucial factor. This holds in particular for triathlon racing where rules disallow drafting such that wind resistance is highly significant.
Measures to reduce wind resistance include in general a streamlined shape of bicycle components on the one hand and on the other hand an optimum riding posture so as to minimize the frontal area. Many cyclists use so-called aero supports which are attached to the handlebar. In addition to aero supports, arm or elbow rests are often provided as a support for the rider to prop his forearms on. The rider can concurrently grip front portions of the aero supports with his hands. This will result in the rider assuming a flat riding posture which will minimize wind resistance.
The pair of aero supports may be designed as separate bars, e.g. terminate bar end-like or they may be joined in front to form a bow. Aero supports are typically mounted at a relatively narrow lateral distance such that in operation the rider will offer a particularly small frontal area.
Handlebars have become known having one-piece, integral aero supports. Typically the handlebar will extend conventionally outwardly from the point of attachment to the stem, the tubes will then bend forwardly from the side edges, approaching one another again to extend forwardly to form approximately parallel aero supports.
The front ends of the aero supports may for example be joined to form a bow. The lateral distance of the two aero supports is narrow, being for example about half the maximum handlebar width. The radii required for bending forwardly require a long tube for the handlebar which therefore has a relatively large weight.
Also, a type of aero supports have become known that attach directly to the handlebar by means of fittings. For this purpose, clamping units may be attached to the handlebar to secure the aero supports to the handlebar.
A fundamental disadvantage in using such clamping units with handlebars is that most of the handlebars are not designed to cope with the heavy stresses and strains. The risk that the handlebar breaks may thus increase which may lead to serious accidents. There is the further disadvantage that the clamping units will optically deface the handlebars.
Then again, if the handlebar were designed for the added stresses by clamping units fastened directly to the handlebar, or if the receiving elements are designed integrally with the handlebar, such handlebar will be heavy in weight even if the user removes the aero supports.
Yet another disadvantage is that the clamping units for securing the aero supports must be especially fitted for different cross-sectional shapes of the handlebars. Apart from standard handlebars having round cross-sections there are for example those being non-circular, e.g. oblate in profile achieve a lower wind resistance. This type of handlebars thus requires specially manufactured clamping elements.
It is therefore the object of the present invention to provide a stem front cap and a stem so as to allow a variable and uncomplicated and also safe use of aero supports.